Estrous cycle modulation of extracellular serotonin in mediobasal hypothalamus: role of the serotonin transporter and terminal autoreceptors
| Autor: | Martha Hotema, Sharmin Maswood, William A. Truitt, Marjay Caldarola-Pastuszka, Lynda Uphouse |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Male
medicine.medical_specialty Microdialysis Serotonin medicine.drug_class Serotonin reuptake inhibitor Hypothalamus Middle Nerve Tissue Proteins Biology chemistry.chemical_compound Estrus Internal medicine medicine Extracellular Animals Molecular Biology Autoreceptors Estrous cycle Serotonin Plasma Membrane Transport Proteins Sex Characteristics Membrane Glycoproteins General Neuroscience Ovary Membrane Transport Proteins Rats Inbred F344 Rats Endocrinology chemistry Estrogen Ovariectomized rat Estradiol benzoate Female Neurology (clinical) Carrier Proteins Developmental Biology |
| Zdroj: | Brain research. 831(1-2) |
| ISSN: | 0006-8993 |
| Popis: | In vivo microdialysis was used to examine extracellular serotonin (5-HT) in the mediobasal hypothalamus (MBH) of male and female Fischer (CDF-344) rats. Females from the stages of diestrus, proestrus, and estrus were used. Additionally, ovariectomized rats, primed subcutaneously (s.c.) with estradiol benzoate or estradiol benzoate plus progesterone were examined. Extracellular 5-HT in the MBH varied with stage of the estrous cycle and with the light/dark cycle. Proestrous females had the highest microdialysate concentrations of 5-HT during the light portion of the light/dark cycle and lowest concentrations during the dark portion of the cycle. Diestrous females had the highest levels during the dark portion of the cycle, while males and estrous females showed little change between light and dark portions of the cycle. In ovariectomized rats, there was no effect of 2.5 microg or 25 microg estradiol benzoate (s.c.) on extracellular 5-HT; but the addition of 500 microg progesterone, 48 h after estrogen priming, reduced microdialysate 5-HT near the threshold for detection. In intact females and in males, reverse perfusion with 3 microM fluoxetine, a selective serotonin reuptake inhibitor (SSRI), or 2 microM methiothepin, a 5-HT receptor antagonist, increased microdialysate concentrations of 5-HT. Estrous females and males showed nearly a 4-fold increase in microdialysate 5-HT in response to fluoxetine while smaller responses were seen in diestrous and proestrous rats. In contrast, proestrous rats showed the largest response to methiothepin. Estrous females showed a delayed response to methiothepin, but there was no methiothepin-induced increase in extracellular 5-HT in males. These findings are discussed in reference to the suggestion that extracellular 5-HT in the MBH is regulated in a manner that is gender and estrous cycle dependent. The 5-HT terminal autoreceptor may exert a greater role in proestrous females; the serotonin transporter appears to play a more active role in the regulation of extracellular 5-HT in estrous females and in males. |
| Databáze: | OpenAIRE |
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